The study investigated the demographic variables as determinants of academic stress among undergraduates of Obafemi Awolowo University, Ile-Ife, Nigeria. The descriptive survey design was adopted for this study. The population comprised undergraduates of Obafemi Awolowo University, Ile-Ife, Osun State. Multistage sampling technique was used to select 699 undergraduates. A total of nine out of the existing 13 faculties were selected using simple random sampling technique. From each faculty, 80 students were selected using convenience sampling technique. An adapted instrument titled: “Questionnaire on Academic Stress among Undergraduate (QAU)” was used to collect data from the students. The Cronbach Alpha and Split-half reliability tests conducted on the instrument yielded positive results of 0.72 and 0.78 respectively. Data collected were analysed using percentage, t-test and Analysis of Variance (ANOVA). The results showed that 59% of undergraduates experienced high level of academic stress. It showed that that there was a significant difference between sex (t-test = 0.20; p < 0.05), age (F (3,678) = 2.888, p < 0.05) and class level (F (4,685) = 5.317, p = .000), whereas, no significant difference was found between place of residence (t = 0.267; df = 688, p > 0.05) and academic stress among undergraduates. The study concluded that there was high level of academic stress among undergraduates. However, factors such a sex, age, year of study and place of residence were not responsible for academic stress among undergraduates.